POLAVARAM DAM FAILURE KILLS 45 LAKHS OF PEOPLE-0


Prof.T.Shivaji Rao,

Director, Centre for Environmental Studies, GITAM, Visakhapatnam

 

 http://gitam.edu/old/www.gitam.edu/science/envstud/envr_achievements/shivajirao.html

 

Browse all the  7(0 to 6) websites on Polavaram dam

  Standard procedures followed by NIOH to prepare dam break analysis reports including Polavaram.  See the following websites to compare how unscientific was the method adopted for Polavaram dam in 1999.
 

http://profshivajirao.googlepages.com/polavaramdam-0 

http://www.financialexpress.com/news/ysr-performs-bhoomi-pooja-for-polavaram-project/118361/ 

http://www.sandrp.in/dams/polavrm_article.pdf [good article on polavaram dam]

http://www.hinduonnet.com/fline/fl2317/stories/20060908001904400.htm   

(floods,2006)

 http://www.hindu.com/2005/12/15/stories/2005121507660600.htm [submersion in Orissa admitted]

http://www.hindu.com/2007/02/15/stories/2007021510890400.htm [Less power?]

http://www.expressbuzz.com/edition/story.aspx?Title=Polavaram+project+will+be+completed:+CM&artid=4WI7IUHXX4s= 

http://www.thehindu.com/2009/01/20/stories/2009012059320400.htm  [False promises of CWC]

http://www.thehindu.com/2009/01/21/stories/2009012153870400.htm  [TAC clearence,last permit]

http://www.thehindu.com/2009/07/14/stories/2009071454980500.htm [Forest clearence awaited]

http://www.thehindu.com/2009/05/02/stories/2009050260540600.htm [planning commission clears,25-2-09]

http://www.hindu.com/2010/01/24/stories/2010012456560400.htm [Rs.4,500 crores,spent on canals]


http://profshivajirao.googlepages.com/polavaramdam-1 

http://profshivajirao.googlepages.com/polavaramdam-2

http://profshivajirao.googlepages.com/polavaramdam-3

http://profshivajirao.googlepages.com/polavaramdamimages-4

http://profshivajirao.googlepages.com/polavaramdam-5

http://profshivajirao.googlepages.com/polavaramdam-6

http://shivajirao32.googlepages.com/polavaramdam-8 

http://shivajirao32.googlepages.com/polavarambarragehanumantharao 

polavaram a BOON to karnataka 

http://www.thehindu.com/2009/05/02/stories/2009050260540600.htm 

http://www.nodig06.im.com.au/pdfs/9%20Rajeev%20Vishnoi.pdf 

The catchment area of the Tehri dam is 7,511 sq. km out of which 2,328 sq km lies above the snow line.http://www.nodig06.im.com.au/pdfs/9%20Rajeev%20Vishnoi.pdf 

Tehri Spillway is a Modern design based on  PMF of 10,000 years return period,estimated at 15,540 cumecs 

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter1.htm 

profshivajirao.googlepages.com/seemakugodavarijalalesaranyam   (Telugu Article) 

(See other chapters  1 to 8 of the above website) 

http://www.sakti.in/godavaribasin/indira-ICad.htm   [Details of Polavaram Project]

http://upload.wikimedia.org/wikipedia/commons/a/af/India_topo_big.jpg[big map]

http://cgwb.gov.in/watershed/GODAVARI.jpg    (detailed sub-basin maps)

http://cgwb.gov.in/watershed/cdgodavari.html   (detailed sub-basin areas)

http://en.wikipedia.org/wiki/Image:India_annual_rainfall_map_en.svg     [Rainfall map,India]

http://www.geocities.com/prof_shivajirao/cloudseedingeffective.html 

For more details on Dam safety,see:

http://books.google.co.in/books?id=3JWS_gHcFt4C&pg=PA1100&lpg=PA1100&dq=New+Trends+in+Hydrological+safety,Berga&source=bl&ots=p0w0KO59zH&sig=c3iA5r0AVriEm2VKCxCazeEsvPA&hl=en&ei=rwiAS8rINozCrAfL_cCwBw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAgQ6AEwAA#v=onepage&q=New%20Trends%20in%20Hydrological%20safety%2CBerga&f=true 

[L.Berga defines First,Second and Third Generation Levels of Hydraulic safety of Dams]

http://www.nodig06.im.com.au/pdfs/9%20Rajeev%20Vishnoi.pdf  

Tehri spillway flood is taken as PMF with 10,000 years return flood  at 15,540 cumecs

http://profshivajirao.googlepages.com/modifyingsardarsarovardam


http://kfki.baw.de/conferences/ICHE/2002-Warsaw/ARTICLES/PDF/129C2.pdf [ Asian Dams]

includes standards followed by China,asian coutries and ICOLD

  [ Public Hearing]http://www.hinduonnet.com/thehindu/thscrip/print.pl?file=2005101113940300.htm&date=2005/10/11/&prd=th&

http://profshivajirao.googlepages.com/nuclearsafety-1

PART-01

 First see web site :  http://www.sandrp.in/drp/feb-Mar2006.pdf

http://www.nih.ernet.in/consultancy.html  [polavaram Dam Break report , inundation map,1999]


Dam-Break Flood Studies of Polavaram Project

This consultancy project  on Polavaram Dam DAM-BREAK Analysis was referred by Environment Protection Training and Research Institute (EPTRI), Hyderabad. The objective of the study is to find the flood hydrograph at different locations in the study area due to hypothetical dam-break. Preparation of the inundation map of the area and sensitivity analysis with respect to breach width, time of failure and bed roughness are also included in the analysis. A sensitivity analysis with respect to breach width shows that the maximum water level elevation increases with the increase in breach length. Sensitivity analyses with respect to failure time and bed roughness have also been presented. An inundation map has been prepared using the results for maximum water surface elevation and contours of the region.

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter5.htm 

Case study of Dam Break Analysis to select best alternate project.contains 5 chapters.To get each chapter on the web site change the numerals from 1 to 5 under the word chapter in the web site

HUNDREDS OF DAM FAILURES EVEN IN USA AND CHINA DUE TO MANY FAULTS

According to the American  Dam safety officers, out of 75,000 dams in USA, several hundreds of them are disasters waiting in the wings. Far too many dams are facing the risks of failure, threatening lakhs of  human lives and billions of dollars worth of properties.  Out of many old dams about 50-year old ones account for 85% of the dams by 2020 and most of these dams were built without adequate spillway capacities to release flood waters during torrential rains, causing extreme floods that overtop the dams ,resulting in their collapse. Even in China the Water resources Minister, Zing Ping recently stated that about 68 dams collapse every year. During the last 50 years about 3500 out of about 85,000 dams collapsed, placing dam collapse rate  at 4%.In Guangdong province 50% of the dams amounting to 3685 are classified as Dangerous Reservoirs.Many cities are under threats of dam collapses and among them are 25.4% of cities with 179 dangerous reservoirs, and16.7% of county towns with 285 reservoirs. In addition to 146 million people, about 9 million Hectares of cultivated fields also face serious threat. In fact in 1975,the collapse of Banquiao Dam caused death of 1,00,000 people due to drowning and 1,40,000 people due to the repercussions of the floods like epidemics and food shortage.

In western countries where scientific opinion is highly respected,knowledge is treated as power to promote the welfare of the people.But in poor countries like India since considerations other than merit  are given utmost importance in decision-making,it is the power that is treated as knowledge .Hence the business lobby influences the  senior administrative officials who in turn influence the decisions to be taken by the politicians and hence the scientific and engineering considerations even in the planning,design and execution of major Irrigation projects get very low weightage.Even Epert committees are constituted by choosing mostly YES men and sometimes people whose fields of specialization fall out side the subjects under consideration.The Constitution of Boards and Technical committees of the pollution control Boards and Ministries of Environment at both the state and central levels are glaring examples of how the officials virtually make the functioning of the Environmental laws most ineffective in public interest and more useful to the vested interests whose business thrives by making maximum profits by avoiding installation of  pollution control measures that help in keeping under check the levels of poisoning of man and nature.

In the case of Polavaram Dam project of Andhra Pradesh,I have been appointed as an Expert committee Member for Environmental Appraisal of the project during 1980’s and I have been studying the problem in depth for over 25 years .During these long years,I had discussions with eminent Engineering experts and most of them have expressed misgivings about the improper design of the spillway and the safety of the Dam and the environment. Since my studies clearly show that it is a prescription for Disaster, I felt it my duty to create awareness among the Environmentalists and the concerned people who can advise the Government to consider the need to convert the Polavaram Dam into a Barrage to serve water needs for drinking and irrigation and to use alternate methods for generating the power as contemplated by the project and thereby provide safety to the dam and to lakhs of people  living downstream of the dam.

 

EXTREME FLOODS IN GODAVARI RIVER (In chronological order)

S.No.

Date of peak flood

Peak flood discharge

Synoptic system

 

 

Thousand cumecs

Lakh cusecs

 

1.

16-8-1953

81.00

28

D  (Depression)

2.

16-8-1962

37.1

13

L  (Low pressure )

3.

22-9-1962

49.8

17.8

D

4.

26.9.1964

25.3

9.0

D

5.

8-9-1966

62.6

22.0

L

6.

29-7-1967

26.9

9.5

L

7.

11-9-1969

25.2

8.5

D

8.

23-9-1969

35.7

12.5

D

9.

23-8-1970

56.7

20.0

D

10.

8-7-1972

21.9

7.7

D

11.

12-7-1973

19.9

7.0

D

12.

17-7-1975

27.0

9.5

L

13.

23-7-1976

54.4

20.0

L

14.

26-8-1977

23.3

8.0

D

15.

18-8-1978

40.5

14.0

D

16.

7-8-1979

30.6

11.0

L

17.

13-8-1981

42.2

15.0

D

18.

16-8-1983

57.9

20.0

L

19.

16-8-1986

99.3

36.0

D

20.

4-10-1988

36.7

13.0

D

21.

27.7.1989

43.1

15.0

D

22.

4-9-1989

27.9

10.0

L

23.

2-9-1990

61.0

22.0

L

24.

20-9-2005

62.0

22.0

D

 25                7-8-2006                         81.5                               28.5                           L


 

NOTE: The data in the above table on extreme historical flood events in River Godavari must be considered to determine the magnitude of return flood flows as per the International norms followed as indicated in the other websites on this subject. 

 http://www.ias.ac.in/jessci/mar2001/E1397.pdf 

 

MODEL EXAMPLE ON DAM BREAK ANALYSIS, RISK ASSESSMENT AND ENVIRONMENTAL IMPACTS IN CASE OF HORSETOOTH RESERVOIR, USA

(to be followed by the Indian engineers concerned with Polavaram and other dams)

 FLOODING PROBLEM:

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter1.htm

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter2.htm

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter3.htm

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter4.htm

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter5.htm

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter6.htm

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter7.htm

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter8.htm

The dams that form Horsetooth Reservoir were modified in 1988-1989 by raising the crests approximately 3 feet to accommodate storage of the Probable Maximum Flood. Therefore, no significant flood issues exist presently at the Horsetooth Reservoir Dams. The ability of the reservoir to handle flood inflows was demonstrated by events during the July 28, 1997, flash flood that occurred in the Spring Creek drainage in the southwestern corner of Fort Collins. A localized storm produced as much as 10 inches of rain in less than 5 hours. Unfortunately, a majority of the rain and resulting flood runoff occurred below the reservoir. The flash flooding in Fort Collins resulted in 5 deaths, numerous injuries, and many millions of dollars in damages. However, Horsetooth Reservoir captured and stored about 4,000 acre-feet of flood runoff during this event, which resulted rise in an elevation of the reservoir water surface of approximately 2 feet. The ability of the reservoir to store a portion of the flood flows helped reduce the death and destruction caused by the flood.

Consequences of Dam Failure

http://www.usbr.gov/gp/ecao/horsetooth/horsetooth_safety_dams/mod/chapter3.htm

A. Population at Risk

Horsetooth Reservoir Dams have a high-hazard classification, based on the population at risk. If one of the dams experienced sudden catastrophic failure, the resulting flood would jeopardize the lives of tens of thousands of people living downstream. The flooding would destroy or extensively damage homes, businesses, property, utilities, and the environment through minor drainages immediately below Horsetooth Reservoir and for an approximately 30 mile section of the Cache La Poudre River between Fort Collins and Greeley, Colorado. Near Greeley the flood waters would enter the South Platte River where the flooding would be somewhat attenuated. The flood plain between Horsetooth Reservoir and the South Platte River contains several communities that would experience complete or partial inundation from a sudden catastrophic failure. These are listed in Table 3-1.

The information presented here assumes a probable maximum flood, which would be an extremely rare event. The U.S. Department of the Interior, Bureau of Reclamation issued an Emergency Preparedness Plan Brief regarding Horsetooth Dams and Reservoir in October, 1983. That document states that a dam failure during a probable maximum flood would inundate or cause severe damage to the following areas:

1) Fort Collins                    2)   Timnath                            3) Laporte    

4) Interstate 25                   5)  Windsor                           6) Kodak Plant    

 7) Portions of Greeley       8) Hardin                               9) Masters   

10) Orchard                        11)Goodrich                       12) Weldona    

13 )Low lying areas of Fort Morgan

Table 3-1   Population at Risk below Horsetooth Reservoir

Dam

City

Population at Risk

Travel Time for Flood Wave Peak (hours)

Horsetooth

Bellvue

356

0.25

Horsetooth

Laporte

2,707

0.7

Horsetooth

Ft. Collins

13,981

1.55

Soldier Canyon

West Ft. Collins

15,763

0.6

Soldier Canyon

East Ft. Collins

17,130

1.5

Dixon Canyon

West Ft. Collins

30,180

0.6

Dixon Canyon

East Ft. Collins

37,139

1.5

Spring Canyon

West Ft. Collins

26,407

0.6

Spring Canyon

East Ft. Collins

34,510

1.5

All Dams

Timnath

678

2-3

All Dams

Windsor - Greeley

23,383

4

A Loss of Life Study and a Risk Analysis were conducted to estimate the consequences of a dam failure at Horsetooth Reservoir. Loss of life estimates vary by dam, failure mode, estimated time for breach to develop, etc. The range of the best estimate of loss of life is summarized in Table 3-2. It should be noted that the majority of the population at risk resides in or near Fort Collins, and dam failures can occur suddenly, with little or no advance warning. A sudden failure of this nature, compounded by the minimal travel time for a flood wave to reach the highly populated area of Fort Collins, would not allow for a sufficient warning to be issued to those living closest to the reservoir. The higher loss of life values in Table 3-2 reflect this scenario.

Table 3.2   Estimated Loss of Life

 

Dam

Estimated Range of Loss of Life

Horsetooth Dam

170 - 5,000

Soldier Canyon Dam

300 - 9,600

Dixon Canyon Dam

680 - 19,700

Spring Canyon Dam

600 - 17,700

 

B. Property Damages and Lost Project Benefits

An estimate was made of potential downstream damages and lost project benefits that would result from failure of Horsetooth Dam. Failure of any of the other 3 dams which retain Horsetooth Reservoir would result in even greater damage because their floodplains would encompass a greater portion of Fort Collins. Thus, in terms of potential maximum damage that would result from failure of any of the dams, the damage estimate is conservative. According to inundation data, failure of Horsetooth Dam would result in damage for about 87 miles downstream and would impact residential, commercial and public property, including infrastructure, throughout the area. All or parts of the communities of Fort Collins, Timnath, Windsor, Greeley, Kersey, Hardin, Masters, Orchard, Goodwin, and Weldona, along with other towns in Larimer and Weld Counties, would be severely damaged or destroyed.

Enumeration of individual properties within the various categories was provided by a computerized remote sensing geographic information system (GIS). The property damage estimates probably overestimate potential losses since they assume total destruction of property within the flood plain. The actual damages would vary with varying water depths and velocities of the flood waters. However, the estimates include only direct damages to structures and contents. No attempt was made to include measures of lost income for business and industry or expenditures that would be required for alternative interim residential shelter and facilities for government, schools, hospitals, etc. Also, as noted, the Horsetooth floodplain is the smallest of the four dams retaining the reservoir. Therefore any overestimation of these direct damages is at least partially counterbalanced by unquantified costs.

In addition to direct damages, dam failure would involve lost project benefits, including irrigation, municipal and industrial water, power, recreation, and flood control, which total about $696 million on a capitalized present worth basis. Thus, dam failure would result in total damages and lost benefits of about $6.4 billion, categorized as follows:

Flood Inundation Damages

 

Residential Property

$1,971,000,000

Commercial Property

$3,143,000,000

Public Property

$ 427,000,000

Infrastructure

$ 183,000,000

Total Estimated Flood Inundation Damages

$5,724,000,000

Capitalized Project Benefits

$ 696,000,000

Total Damages/Lost Benefits Due to Dam Failure

$ 6.4 billion

         

EXPLANATORY NOTES FOR THE FIGURES AND GRAPHS PRESENTED UNDER POLAVARAMDAMIMAGES-4 WEBSITE

 

Fig -1 represents the Log-Log graphical presentation  indicating the relationships between the return period of the floods used for determining the size of the dam for providing adequate storage for flood control and the peak floods that can be safely  discharge through adequate size of the spillways.  Thus the probable maximum flood has to be scientifically estimated for optimizing the sizes of the dams and spillways to ensure the based upon the hazard potential due to a hypothetical dam failure.  The tables below the graph also indicate proportional factors and the extreme flood discharges for different return period.

Fig-2 is a colourful artists view of the Machchu dam before and after its collapse due to erroneous  design flood assumed by the engineers for design of the dam and its spillway.  This is one glaring example of several hundreds of dams that collapsed in all the countries including India mostly due to the improper planning execution and maintenance of dams by the irrigation engineers.

Fig-3  is an important illustration on incremental increase of floods produced by the transformation of the enormous man-made reservoir storage behind the dam which gets added to the natural extreme floods caused by torrential rainfall and sometimes by the collapse of man-made damsin the upper states of river basin.  This clearly indicates that while people have a chance to protect their lives from natural flood as had happened in Godavari in August 1953 and August 1986 they have no chance at all to save themselves from the sudden flash floods caused not only by the natural peak floods but also by the additive impact of man-made reservoir floods that will be 2 to 3 time far higher than the extreme natural floods.

Fig-4  is a graphical representation of the peak flood elevation due to a hypothetical dam failure at Polavaram for different storage capacities of 200 TMC, 110 TMC and 70 TMC which clearly shows that larger the  height of the dam greater will be the risks to loss of life and properties and this clearly shows that Polavaram dam must be converted into a small sized barrage to satisfy all the agricultural needs of the state excluding hydro-power generation but provides for safety of the project and the people becomes more economical for the state.

Fig-5  is a map of the Polavaram dam area and the other areas of Godavari delta that will be submerged due to intense floods caused by a hypothetical dam failure due to a maximum credible accident.

The tables below this figure indicate the input data fed to the computer software, NWS dambreak model and the output data has been presented in the previous pages which shows the villages, towns and cities with a population of 45 lakhs of people who will be victimized due to a dam failure.

Fig-6 shows the Indian Earthquake highways and danger zones.  This figure clearly shows that Godavari river is in a rift zone and they Bhadrachalam under the Polavaram project has already faced an earthquake of magnitude 5.7 on the Richter scale and due to reservoir induced seismicity the dam may face a seismic threat like its counter part at Koyna located in a similar seismic highway.  The subsequent pages from the Environmental Impact reports from Polavaram dam clearly show that dam break analysis report is not only incomplete but also shows that with limited data presented.  The experts warned that Rajahmundry and Kovvuru regions will be submerged  under flood waters upto elevation of 25 to 30 meters, the report is presented extensive inundation zones by means of maps and tables which have not been presented to the concerned people during the public hearing as envisaged by the rules and regulations of the Environmental Protection Act.  The state Government has not made any risk assessment and consequently the disaster management plans which are the basic foundations for obtaining environmental clearances from the Union Ministry of Environment and Forests.  The disaster management report is based upon wrong assumptions because the previous historic flood of August 1986 which should have been normally taken as a 150 year return flood has been presumed to be a 500-year return flood and this flood is again mistakenly assumed to be the probable maximum flood as per the International standard norms already mentioned in the paper.  In the absence of these crucial reports it was not possible for the state Government engineers to make any genuine attempts to consider several alternatives to the project to arrive at a proper cost benefit analysis of the project and to ensure safety of the dam and the lakhs of people who will be facing  a watery grave due to a dam failure.

The Union Ministry of Water Resources who have conducted dam break analysis reports for a large number of dams in other states like Rajasthan, Madhya Pradesh, Orissa and Tamil Nadu by using the World Bank assistance have miserably failed to conduct similar dam break studies for Polavaram dam to ensure safety of the project and the lakhs of people in the downstream of the dam.

The last 3 graphical presentations are self explanatory and they are used to estimate the maximum peak floods resulting from the collapse of a dam based on storage capacity in one graph and both volume of storage and height of the dam in the subsequent figure.  The last graph is more or less a reputation of the graph in Fig-1 including the table tables and the same explanation apply.

 SPILLWAY DESIGN FLOOD (SDF) FOR DAMS IN VIRGINIA,USA

(http://legis.state.va.us/codecomm/register/vol18/iss14/f4v5020.doc)

Class of Dam

Hazard Potential if dam fails

Size Classification

Spillway Design Flood (sdf)

Maximum capacity (Ac.ft

Height (ft)

I

Probable Loss of life, Excessive Economic Loss

Large  >  50,000

Medium   1,000 to  

                50,000

Small   50 to 1,000

>100

  40 to 100

 

 25 to 40

PMF

PMF

 

0.5 PMF to PMF

II

Possible Loss of Life; Appreciable Economic Loss

Large  >  50,000

Medium   1,000 to  

                 50,000

Small      50 to 1,000

>100

  40 to 100

 

  25 to 40

PMF

0.5 PMF to PMF

 

100-YR to 0.5 PMF

III

No Loss of Life Expected; Minimal Economic Loss

Large  >  50,000

Medium   1,000 to  

                50,000

Small      50 to 1,000

>100

  40 to 100

 

  25 to 40

0.5 PMF toPMF

100-YR to 0.5 PMF

50-YR to 100YR

IV

No Loss of Life Expected; No Economic Loss to Others

> 50 (non-agricultural)

> 100 (agricultural)

>25 (both)

50-YR to 100-YR

Statutory Authority:  § 10.1-605 of the Code of Virginia.

Effective Date:  July 1, 2002.

1)  PMF: Probable maximum flood. This means the flood that might be expected from the most severe combination of critical meteorologic and hydrologic conditions that are reasonably possible in the region. The PMF is derived from the current probable maximum precipitation (PMP) available from the National Weather Service, NOAA. In some cases local topography or meteorological conditions will cause changes from the generalized PMP values; therefore, it is advisable to contact local, state or federal agencies to obtain the prevailing practice in specific cases.

2)  50-Yr: 50-year flood. This means the flood magnitude expected to be equaled or exceeded on the average of once in 50 years. It may also be expressed as an exceedence probability with a 2.0% chance of being equaled or exceeded in any given year.

3)  100-Yr: 100-year flood. This means the flood magnitude expected to be equaled or exceeded on the average of once in 100 years. It may also be expressed as an exceedence probability with a 1.0% chance of being equaled or exceeded in any given year.

 

 Flood Damage to Dams (A 500-year flood of 1965 was changed to 1000 year flood for safety) :  In the case of Polavaram dam a 500-year return flood was used for spillway design amounting to the historical flood of August 1986 of 36 lakh cusecs.  Even a 1000-year return flood which is a multiple of 500-year return flood cannot be considered adequate because of the high hazard potential of downstream villages, towns and cities which require the spillway design to be atleast 1.0 PMF and hence Polavaram dam spillway design itself is unsafe.  A similar case study from USA is enclosed here.  http://www.permatopia.com/wetlands/dam.html All of the Corps dams were designed and built with specific flood capacities. Current dam designs are based on Standard Project Floods. Standard Project Floods, as defined in the Corps Engineer Manual 1110-2-1411 (March 1, 1965) are floods resulting from the Standard Project Storm. In turn, the Standard Project Storm is defined, somewhat imprecisely, as the most severe flood-producing rainfall-snowmelt, depth-area-duration event that is considered “reasonably characteristic” of the drainage basin. Discussions with Corps staff in the Portland District Office indicated that the Standard Project Flood is approximately a 500-year flood event.

The Corp dams’ discharge design levels include the combination of spillway discharge capacity and reservoir outlet pipe discharge capacity. For example, for the Hills Creek Dam, the Standard Project Flood is 64,500 cubic feet per second. The maximum controlled discharge capacity of the dam is 151,760 cubic feet per second, or nearly two and one-half times the Standard Project Flood discharge. These data are included on the Hills Creek Project, Emergency Response Flowchart7. At discharges beyond the maximum controlled discharge capacity of the dam, the dam would be overtopped, discharges would be uncontrolled, and there would be a high probability of damage to the dam, with some potential for dam failure. The large margin of safety in the discharge capacity of the dam suggests that the Hills Creek Dam likely has the capacity to withstand floods at least as large as a 1,000 year flood event without expected damage. The other Corps dams have similar margins of flood design safety. 

for other articles on cloud seeding see the following websites

profshivajirao.googlepages.com/coldcloudseeding
profshivajirao.googlepages.com/cloudseedingurgentneedofindia
http://profshivajirao.googlepages.com/cloudseedinghistory
profshivajirao.googlepages.com/cloudseedingbyagriculturists
profshivajirao.googlepages.com/cloudfeatures
profshivajirao.googlepages.com/cloudseedingquestions
profshivajirao.googlepages.com/cloudseedingelectricity
profshivajirao.googlepages.com/warmcloudseeding